Printing input and output device for a computer



Oct. 14, 1958 R. w, WOODWARD EI'AL 2,856,130

PRINTING INPUT 'AND OUTPUT DEVICE FOR A COMPUTER Filed June 29, 1954 2Sheets-Sheet 1 INVENTO RAVMOVD W ARD R/CH4RD W XERKS A TTORNEY T Oct.14, 1958 R. w. WOODWARD ETAL 2,856,130

PRINTING INPUT AND OUTPUT DEVICE FOR A COMPUTER 2 Sheets-Sheet 2 FiledJune 29, 1954- INVENTOR. RAWCWD WWOODMRD RICHARD W YER/(S United. StatesPatent PRINTING INPUT AND OUTPUT DEVICE FOR A COMPUTER Raymond W.Woodward, West Hartford, and Richard W. Yerks, Manchester, Conn.,assignors to Underwood Corporation, New York, N. Y., a corporation ofDela ware Application June 29, 1954, Serial No. 440,014

2 Claims. (Cl. 235--145) This invention is directed to a device forindexing and printing values to be entered into a computer device at adistance therefrom and more particularly to a printing mechanism bywhich values may be mechanically set up for printing and simultaneouslyelectrically transmitted to a remotely located computer mechanism forentry therein.

It has been found when a mechanical printing device is used as the inputdevice for an electrically controlled computer, that errors sometimesoccur due to incomplete operation of an input key. Such errors occurbecause of the dilficulty in setting adjustments such that an indexeddigit is mechanically set up and electrically transmitted at the sametime. If a digit key is depressed only far enough to control only one ofthese functions, obvious discrepancies and errors will occur. It is,therefore, necessary to provide a mechanism by which a key, whenoperated far enough to control one function, shall be positivelydepressed to perform its other function.

It is an object of the present invention to provide a mechanism whichmay be manually indexed to set up a value for printing and tosimultaneously transmit the set up value to a computer for entry thereinand to provide a feed back interlock to insure that the values asprinted and as entered shall be identical.

It is another object of this invention to devise a printing mechanismfor controlling a computer which in turn controls the printing mechanismto determine that the printed value shall agree with that entered intothe computer.

With these and other objects in view, the invention comprises certaincombinations of elements as set forth in the preferred embodimentdescribed hereafter and shown in the appended drawings.

In the drawings,

Figure 1 is a side elevation of a section of the printing device of theinvention,

Figure 2 is a perspective showing of one of the key mechanisms of thedevice,

Figure 3 is a side elevation of the operation control keys of thedevice,

Figure 4 is a perspective showing of a portion of Figure 3, and

Figure 5 is a schematic diagram of a portion of an electronic computerusable in cooperation with the present invention.

The input-output device of this invention is modified from a commercialadding machine of the well known Underwood Sundstrand type but obviouslyany type of indexable ten key printing device may be used with onlyminor modifications. The computing mechanism controlled by the disclosedinput-output device may be either electrical or electronic and is to becapable of receiving digital inputs in decreasing denominational orderand of utilizing these inputs as addresses, instructions, or foraddition or subtraction, such as the Elecom electronic computers.

Referring now to the accompanying drawings, Figures ice 1 and 2 show aplurality of digit keys 10 each on a stem 11 slidable in top and bottomplates 12 and 13. Each key stem 11 has a lug 15 in engagement with anear 16 projecting rearwardly from a rocking cradle 17 all of whichcradles are pivoted in side plates, not shown, to press rearwardly, whenrocked, one of the links 18, each link pivoted at its rear end on one ofa group of levers 20. Also pivoted on each lever 20 is a push rod 21,all rods 21 being slidably supported at their rear ends in a post 22secured to a swinging arm 23. A post 25 in engagement with the rearedges of levers 20 is secured between top and bottom levers 26 foroperation by any lever 20. An escapement rod 27 connected to the upperlever 26 is also supported at its rear in post 22 to operate anescapement arm, not shown, to enable a one step advance of swinging arm23 for each depression of a key 10.

In alignment with the rear ends push rods 21 at each position of arm 23is a column of settable index pins 30 to be set rearwardly by operationof keys 10 to represent a set up value. Slidably mounted on a shaft 31below pins 30 and connected to arm 23 is a slidable guide 32 supportinga plurality of tail pins 33 secured to arms 35 of type bars 36. During amachine cycle, arms 35 and type bars 36 are released to move upwardlyuntil their respective tail pins 33 engage an aligned set pin 30 andarrest bar 36 thereby aligning a type 37 of bar 36 with the usual typehammers for printing on platen 38. The mechanism thus far described isthe same as that set out in U. S. Patent No. 1,583,102, issued May 4,1926, to Oscar J. Sundstrand and embodied in the commercial Sundstrandadding machine to which reference is made for further details ofconstruction not fully disclosed herein.

To transmit to an associated computer, the digits which are set up inpins 30 by keys 10 to be printed by type 37, each key stem 11 hassecured thereto a bevelled stud 41. Secured to the top keyboard plate 12is a plurality of switches 42 which may be electrically connected to thecomputer to control the digital values entered therein. Each switch 42comprises, Figure 2, a stationary blade 43 and a movable blade 44 havingan insulating stud 45.

The bevelled stud 41 of each key stem 11 during depression of a key 10will contact the stud 45 to close the switch 42. The relationship ofstuds 41 and 45 is such that switch 42 will be closed before the pushrod 21 associated with the operated key 10 has fully set the aligned pin30.

Secured to the lower end of each key stem 11 below plate 13 is anarmature 47, each armature being positioned in a coil 48 of one of agroup of solenoids fixed to the machine base, not shown. These coils 48are energized as will be later described under control of the switches42 through the associated computer to fully depress an operated key 10while the digit value is being entered into the computer, therebypositively setting the stop pins 30 and insuring that the printed andcomputed values are the same.

A portion of one form of electronic computer which may be used tocontrol the energization of solenoids 48 is shown in Figure 5. In thecircuit shown, the stationary contact blades 43 of all switches 42 areconnected to a common wire 50 which is connected through a resistor 51to a source of positive voltage. The movable contact blades 44 areindividually connected by leads 53 to one end of resistors 54 all ofwhich are grounded at their other ends. The leads 53 are each connectedthrough a buffer circuit 55 to the grid 57 of a thyratron tube 58. Thecathodes of all thyratrons 58 are connected through resistors 59 to acommon cathode voltage lead 60 and the anodes are individuallyconnected. through cabled leads 62 to one side of the coil 48 associatedwith the digit key stem 11. The other leads of coils 48 are connected topositive voltage lead 63 which may be deenergized at an appropriate timeto terminate conduction in any thyratron tube. As thus far described,it'will *be evident that upon depression of any'key '10, the voltage oflead 50 will be applied through switch 42 and buffer 55 to the .grid ofan associated thyratron 58 .causing it to become conductive. The currentpassing through the thyratron energizes the coil 48 and therebypositively depresses key to the fullest extent and'holds it there, thusinsuring that the keys will be fully operated to index pins forcontrolling printing of the .value'entered.

The thyratrons .58 may also be .fired by voltages applied to their grids57 by individual leads 64 connected to buffers to enable coils 48 toindependently operate keys 10 to print a total'valueunde'r control ofthe computer.

As the voltage at the cathode ofa thyratron '58 rises when the tube isfired, this voltage may be used :to control the digital entry into thecomputer circuits and leads 65 individually connected to the thyratroncathodes are provided for this purpose. It will be understood thatbuffers "55 are wellknown devices'in the 'electronic'field and willpermit a voltage applied to any input .lead 'to be applied to theoutputlead without'any effect on other inputleads. A gating device asused in a hereinafter described part of the circuit is a device in whichall of the input leads must be at a positive voltage before the outputlead may become positive. These buffers and gating devices may be thesame as those disclosed in the application of Samuel 'Lubkin, Serial No.370,538, filed July '27, 1953, and entitled Electronic IDigitalComputer.

To extinguish a fired thyratron 58' and permit release of an operatedkey 10 after the computer'has'received the transmitted digital value, ,atiming circuit isprovided. Connected between lead 50 :and asource ofnegative bias voltage are two resistors 66 and 67 in series. Anamplifier 70, similar to those of the above Lubkin application, isconnected at its-input end to *the junction of resistors 66 and67 and isso connected that when the'input voltage becomes more negative as itdoes when any switch .42 is closed, output lead 71 will be shifted froma negative to a positive voltage. This voltage on lead 71 is applied'toa gate 72'whichit will be remembered can pass a positive voltage onlywhen all input leads are positive aswill-be later-set out with referenceto amplifier 87. Input lead 73 is normally positive but lead 74 becomespositive only momentarily at the start of a set up cycle when thecomputer is conditioned to receive a value input. At this time all leadsto gate 72 are positive and a positive signal passes through butter 76to a gate 77. The other 'input 78 to gate 77 is normally positive, goingnegative only when the computer has received a digital value, and thesignal will pass through gate 77 and amplifier 79 to make positive anoutput lead 80 which permits the computer to receive a set-up digitvalue. Lead'80 forms the other input to butter 76 and when positiveserves to continue feeding a positive voltage togate 77 and amplifier 79after input 74 becomes negative, thus constituting a holding circuituntil lead 78 is made negative. The positive voltage of lead 80 is alsoapplied to a gate 81 which, at a-time just before a set up cycle ends,receives a positive voltage pulse on its lead 82. The positive output ofgateS-l is passed through a butfer 85 toa gate 86itheother input 71 ofwhich was made positive when a key was depressed .and therefore :thecombination of "positive inputs to gate 86 passes to the input of anamplifier 87. The output 88 of amplifier 87 then becomes positive and isfed back to buffer 85 to maintain the amplifier input positive so longas lead 71 is positivedue .to a key being held depressed. Lead 73previously referred to is a negative output of amplifier 87 and becomesnegative when a positive input is applied'to amplifier 87. This negativevoltage is applied to gate 72 and prevents a second digital set up cycleby holding lead 80 at its negative value. The positive lead 88 energizesa relay coil 89 to move the contact 90 supplying voltage to thyratrons58 to a ground contactthereby extinguishing the thyratrons and releasingkeys 10. If a key 10 is held depressed manually, the more negativevoltage applied to the input connection of amplifier 70 is continued tohold output lead 71 at a positive voltage. This positive voltage on lead71 is applied through gate 86 as above set out to the input of amplifier87 to energize relay coil 89 and prevent firing ofaany thyratron, andonly when the depressed key is released does the circuit return to itsoriginal voltage condition.

This timing circuit is thus set by depression of a digit key to energizethe associated computer over lead 80 for. one set up cycle and atthe endof that cycle, the fired thyratron is extinguished and the computerinput disabled .until the depressed .key is released.

Inasmuch as the computer is remote from the printer unitasabove:described, it is necessary to have the computer operation controlled bythe same keys which cause printingof the digital set up. As shown inFigures 3 and 4, there are three keys which cause printing of a set up.value and .these keys are :connected to control computer :operation.These keys are the address key 92, the :add key 93, and the subtract key94 and .aremechanically the'same as the motor keys of the UnderwoodSundstrand adding machine and for this reason will be but brieflydescribed. The motor which energizes the printing mechanism iscontrolled by a bent wire 96 ,pivotedat its .rear end and having itsfront end in aslot of a slide 97 mounted for vertical movement. Slide 97maybe depressed by each motor key to start the printingcycle, key93-having a stud 98 thereon, the stud being positionedintthe bottom of aslot of slide 97 and each ,of keys 92 and 94 having a stud 99, 100thereon inengagement with an arm 102, 103 pivotally connected to .slide97. To start a computer cycle at the same time as a printing cycle isstarted, keys 92 and 93 each have-a stud 104, 105 thereon, each studretaining open a switch :106, 107 associated therewith, and each switchwhen closed'starting an appropriate cycle of the computer.

For enabling subtraction in the computer, key '94 :is provided, but theswitch 108 controlled by stud 109on this .key isnot directly connectedto initiate .a cycle of the computer and instead merely prepares thecomputer, the actual subtraction operation being initiated at a latertime. To provide the subtraction initiating impulse, another switch-1-10 is providedto be operated by a part of the printer during theprinting cycle. Key

. 94 is provided with a cam 112 secured thereto, which cam duringdepression of key 94 will move rearwardly a slide 113 by contact of cam112 witha stud 114 on the slide. Slide 113 is latched in its rearwardposition by allever :118 which is spring pressed into a notch of slide113, and the slide in its rearward position releases a symbol type bar116 similar to type bars 36 but provided with different type faces, forone extra step of movement during the machine cycle to print a signal.During this extra step of movement, an ear 117 will engage the front endof' lever 118 which is pivoted on a stud '119 to depress its rear end torelease slide 113 and to close the contacts of switch to start thecomputer .in its subtraction cycle. A spring 120 connected between therear of lever 118 and a stationary :machine part serves to normally holdlever 118 against the bottomof slide 113.

A magnet 121 with its armature 122 secured to the rear of slide 113 isprovided to enable thecomputer to initiate a printing cycle for totaltaking by a rearward movement of slide .113, alever 123 connected tocycle initiating slide 97 being struck by a stud 124 on slide 113 todepress slide 97.

The above description is of a preferred embodiment of my invention andis not to be taken as limiting the scope of the invention as set forthin the appended claims, as many variations of structure are obviouslypossible within the scope of the following claims.

What is claimed is:

l. A combined key set printing mechanism and electrically controlledcomputing device comprising a plurality of digital keys, a plurality ofsettable index members arranged in denominational rows, an index membersetting mechanism between said keys and said members, a switch for eachof said keys, said switch being operated by said key during keydepression and prior to setting of an index member, a solenoidoperatively connected to each of said keys and each said solenoid beingenergizable to depress its connected key to a fully depressed position,input receiving means in said computing device settable by said switchesto energize the solenoid connected to the key which has been partiallydepressed to close a switch whereby said key is fully depressed to setone of said index members, and delay means in said computer to resetsaid input receiving means to dcenergize said solenoid and release saiddepressed key for restoration to a home position after said computer hascompleted entry of the digit corresponding to the operated digital key.

2. A combined printing and computing machine comprising printingmembers, a field of settable index members arranged in paralleldenominational rows to control said printing members, a plurality ofdigit keys,

each key being depressible to set said index members and setting membersbetween each of said keys and said index members to set a stop member ina denominational row and to thereafter initiate a relative shift betweensaid setting and index members and between said index members and saidprinting members, an electrically controlled computer digitally anddenominationally settable by selective energization of a plurality ofinput circuits, a switch in each of said input circuits, a member oneach of said digital keys to operate one of said switches by partialdepression of said digital key, a solenoid connected to each digitalkey, a circuit closing member to energize each solenoid, and therebyfully depress the associated digital key, each circuit closing memberbeing controlled for operation by one of said input leads, and means insaid computer to restore an operated circuit closing member to normalcondition and thereby deenergize an energized solenoid despite manualretention of a key in a depressed position.

References Cited in the file of this patent UNETED STATES PATENTS1,357,423 Robb Nov. 2, 1920 1,504,576 Pope Aug. 12, 1924 1,514,954Crumpton Nov. 11, 1924 1,753,991 Langford Apr. 8, 1930 1,972,985 GardnerSept. 11, 1934 2,036,659 Talley Apr. 7, 1936 2,293,127 Fishack et al.Aug. 18, 1942 2,615,633 Furman et a1. Oct. 28, 1952 2,659,533 Quinby etal. Nov. 17, 1953

